Field of the Invention
The present invention relates to a valve module including a plurality of valve discs and to a steam turbine and a power generation system including the same.
Description of the Related Art
A steam turbine plant includes a steam generator, which generates high-pressure steam by heating a working fluid to a high temperature in a boiler. The steam pressure generated in the steam generator rotates a turbine, and the rotational force of the turbine rotates an electric generator, thereby producing electric power.
In general, a steam turbine plant includes a boiler, which generates high-temperature and high-pressure steam using a heat source such as thermal energy or nuclear energy, and a turbine, which generates drive force for driving an electric generator using steam supplied from the boiler. In order to improve the operational efficiency, the steam turbine plant includes multiple turbines whose operating pressures are different from one another, namely, a high-pressure turbine, a medium-pressure turbine, and a low-pressure turbine. The amount of steam generated in the steam generator and supplied to the turbine via a control valve is controlled depending on the pressure of the steam. At this time, the output of the turbine is controlled according to the opening degree of the control valve.
Such a control valve is typically large and is manufactured in accordance with other large-scale power plant equipment. In order to optimally design a control valve, and more specifically to determine in advance the valve's flow rate characteristics according to its opening degree, performance testing is carried out while the control valve is installed in a common wind tunnel, whereupon the inlet pressure and the outlet pressure of the control valve are compared with each other.